Photo/Illutration The skies are painted in magenta in photographs submitted by citizens. (From Scientific Reports)

Using photographs taken by the public, scientists found startling information about auroras observed around Japan in May and may have fueled a trend in studies of such natural phenomena.

“The latest case highlights how important citizen science is,” Ryuho Kataoka, an associate professor of space physics at the National Institute of Polar Research, said in a statement. “This method will certainly become increasingly significant from now, beyond our scope of research.”

The team consisted primarily of researchers from the institute.

In May, Kataoka on X (formerly Twitter) called on people to check “the northern sky from your homes for possible auroras,” and to send photographs to the team.

A few days earlier, a solar flare, or a massive explosion on the sun’s surface, occurred. This triggered a magnetic storm that sent electrically charged particles into the Earth’s atmosphere, creating auroras over various locations worldwide.

Kataoka expected photos from the public would help determine the extent of the spread of the auroras.

Images poured in from X users. He ended up receiving 775 reports, including some confirming “no auroras” in their areas.

The northern lights were reported even in low-latitude sites where auroras are rarely seen under normal conditions. The southernmost location with aurora sightings was Hyogo Prefecture.

Through the citizen accounts and photos, the researchers estimated the angle at which the aurora was observed from each location.

Auroras usually appear up to 600 kilometers above ground. However, the scientists calculated that the May auroras reached heights of 1,000 km.

“We doubted our calculation’s accuracy again and again, thinking that auroras cannot exceed 1,000 km in height,” Kataoka recalled.

This unprecedented height made the auroras visible even from low-latitude regions.

Another factor that puzzled the researchers was the color of the northern lights. Auroras are typically red in mid-latitude areas like Japan, but the lights captured in the photos were all magenta, or reddish purple.

IONS EXPLAIN MAGENTA COLOR

The auroras appeared magenta from the ground likely because their red color was mixed with a bright blue hue generated by sunlight’s collisions with nitrogen molecular ions in the air, the team said.

In that time of year, sunlight reaches such heights even at night.

Nitrogen molecular ions do not normally exist at a height of 1,000 km. But they can when the air is heated and abnormally expanded by the intense activity of auroras.

Through computer simulations, the team concluded the magenta color resulted from a massive volume of nitrogen molecular ions lifted by a large-scale magnetic storm.

Kataoka was so impressed by the outcome from the photos sent in by the public that he included “citizen scientists” in the acknowledgements section of the team’s published paper.

The researchers’ article was released on Scientific Reports at (https://doi.org/10.1038/s41598-024-75184-9).

Related News